Bullet trap

ABSTRACT

A bullet decelerator and arrestor utilizes a stacked assembly of bullet arresting discs alternating with resilient discs. The disc assembly is enclosed by pliable material and contained within a grenade assembly or other body to be accelerated by the bullet.

United laics Pafiem Driscoll 1 May 23, 1972 [541 BULLET TRAP 2,853,008 9/1958 Bowles ..l02/65.2 3,439,615 4/1969 Forman ct al ..l02/65.2 lnvemofi John Brim", Pans France 3,491,693 1/1970 Streckfuss =1 al ..l02/65.2 [73] Assignee: Allled Research Associates, Inc., Concord,

Mass Primary Examiner-Verlm R. Pcndegrass Attorneyl(cnway, Jcnney & l-lildreth 22 Filed: Aug.7,1969

21 App]. 190.: 848,174 [571 ABSTRACT A bullet dccclcrator and anestor utilizes a stacked assembly 52 US. (:1 ..102/65.2, 42 1 of bull arresting discs alternating with miliwt discs- The [51] Int Cl F4 1/12 disc assembly is enclosed by pliable material and contained 58 Field ofSem-ch ..102/65.2; 42 1 F within a mnfldc asscmbly or y to be accelerated y the bullet. [56] References Cited UNITED STATES PATENTS Brandt ..l02/65.2

9 Claims, 7 Drawing Figures (B n 6 l5 l6 IS 20 L m /W s\ 1 \I i 1 .1 1 1 1 L PMENTEDHAY23 I972 3,664,263

sum 1 or 2 INVENTOR JOHN J. DRISCOLL M z/wm ATTORNEYS PATENIEDMAY 23 1972 3, 664, 263

sum 2 0F 2 JOHN J. DRISCOLL ATTORNEYS BULLET TRAP Rifle grenades were first fired by utilizing special blank cartridges. The expanding gases from these cartridges provided the force to propel the rifle grenades. This system complicated supply logistics since an additional special cartridge had to be manufactured and distributed. It also created tactical problems for the individual soldier wishing to utilize rifle grenades. Therefore, attempts have been made to produce satisfactory rifle grenades which would be propelled by standard ball ammunition.

Two examples of the prior art are U.S. Pat. No. 1,900,790 which discloses a tapered tube with a series of spaced flat discs and U.S. Pat. No. 2,853,008 which discloses a series of flat discs separated by washers. With both of these prior art devices there is a tendency to crack the outer wall of the grenade tube assembly upon firing. Furthermore, with structures such as that disclosed in U.S. Pat. No. 2,853,008 the tubular section of the grenade containing the bullet decelerator may be bulged outwards when the bullet penetrates the arresting discs. When a tubular launcher is used this expansion can lock the grenade to the weapon rendering the weapon inoperable.

An even more serious problem for the individual soldier is the tendency of metallic particles to escape from the rear of prior rifle-grenade bullet traps. Such particles are, of course, unsafe and unnerving to the riflemen.

Accordingly, it is an object of the present invention to provide an improved bullet decelerator and arrestor which contains the bullet without deformation of the exterior surface of the bullet trap portion of the rifle grenade.

Another object is to provide an improved bullet trap which prevents the escape of metallic particles from the bullet trap.

These and other objects are achieved by a structure which includes a deformable layer surrounding the discs which stop the bullet. Additional resilient discs close the openings made by the bullets travel to prevent the escape of metallic particles to the rear.

These and other features of the present invention are described in the following specification in conjunction with the drawings wherein:

FIG. 1 is a cross sectional view of a rifle grenade with bullet trap in place on a muzzle section of a rifle barrel;

FIG. 2 is a cross sectional view of a preferred embodiment of the bullet trap;

FIG. 3 is a cross sectional view of the embodiment of FIG. 2 after it has arrested a bullet;

FIG. 4 is a cross sectional view of another embodiment of the present invention;

FIG. 5 is a cross sectional view of the embodiment of FIG. 4 after it has stopped a bullet;

FIG. 6 is a perspective view of a one-piece disc and washer combination for use in bullet traps of the type shown in FIG. 4; and

FIG. 7 is a cross sectional view of an embodiment employing an annealed tube structure.

Referring now to FIG. 1 a rifle grenade incorporating a bullet trap according to the present invention is shown in firing position at the end of a rifle barrel 1. The rifle grenade is provided with a fuse section 2 and warhead 4 both of which may be of any conventional type. The rear of the rifle grenade incorporates a tubular section 6 with stabilizing fins 8. The stabilizing fins are not part of the present invention and may be of conventional rigid or folding type or may be omitted if the additional stability provided by the fins is not deemed necessary for the particular application.

The bullet trap of the present invention is contained within the tubular section 6. This bullet trap assembly 8 incorporates a pliable, deformable liner 10 adjacent the tubular section 6. As shown in FIG. 1, the pliable liner 10 is closed at the end toward the rifle muzzle 12, but while desirable, this closure is not essential. Within the tubular section 10 there is a series of stacked discs and rings. This stack preferably begins with a ring adjacent the muzzle. As shown ring 14 with a resilient section 15 filling its center portion is the first element of the stacked assembly. The next element is a disc 16 made of steel or other material possessing high resistance to the passage of a bullet. The ring 14 may be made of a light metal or even plastic. After the disc 16 there is another ring section 18 with a resilient center filling l9, and the stack continues in this alternating fashion until it terminates in a solid section 20 at the forward end of the bullet trap.

Referring now to FIG. 2 a preferred version of the bullet trap is shown. The tubular portion 6 of the bullet trap is in place over the muzzle end of the barrel 1 and a bullet 3 is shown nearing the end of the barrel. The bullet trap assembly 8 of FIG. 2 has an encasing yieldable tubular covering 10 adjacent to the rear tubular section 6 of the rifle grenade. At the rearmost portion of the bullet trap a resilient disc 22 begins the stack of bullet trap elements. As shown in the drawing, the layer 10 is completely closed at the end adjacent to the disc 22 and the comers of the disc 22 have yielded into a curved form. While complete enclosure is not essential, it is desirable to provide a simple, sealed assembly. Adjacent to the resilient disc is a disc 16 of bullet-resistant material such as metal or a bullet-resistant ceramic or plastic material. These discs continue in alternating fashion until the bullet trap assembly terminates in a solid section 20. When the elements are identical to those of FIG. 1, identical numerals have been used.

FIG. 3 shows the bullet trap assembly of FIG. 2 after the bullet has been stopped by the bullet trap. A hole 26 has been punctured in the pliable liner 10 as the bullet entered the bullet trap. The first resilient disc 22 contains a perforated portion 28 where the bullet has traveled through the resilient discs. The resiliency of the disc material has caused the opening to be closed again after the passage of the bullet 3. The resilient disc may be fabricated of materials such as rubber, polytetrafluoroethylene or other resistant yieldable materials.

After penetrating the resilient disc 22, the bullet has pierced arresting disc 16, imparting some of its energy to the bullet trap in the process. Since the disc 16 is of strong bullet resistant material, rather than resilient yielding material, the opening in disc 16 remains after the passage of the bullet. Moreover, the disc 16 is expanded somewhat so that it has a larger diameter after the passage of the bullet. The larger diameter of disc 16 causes the liner 10 between disc 16 and the tubular section 6 of the bullet trap to be compressed. Since the liner 10 is pliable, the material is partially compressed and partially extruded to compress the resilient disc on each side of disc 16. This compression serves to more positively close the opening made by the bullet as it passes through resilient disc 22 and the companion, similar resilient discs which alternate down the remainder of the bullet trap. The bullet finally comes to rest in the forward portion of the bullet trap assembly, having imparted all of its forward momentum to the rifle grenade. Thus the rifle grenade is launched through the use of standard ball ammunition. At the portion of the bullet trap where the bullet 3 comes to rest the expansion of the arresting discs is taken care of by deformation of the liner l0 and the resilient discs which alternate with the arresting discs.

Since the bullet trap is provided with a pliable yieldable layer 10 adjacent to the tubular wall 6 the tubular wall 6 has not been bulged or deformed by the expansion of the arresting discs 16. Rather this expansion has been taken up by deformation and compression of the liner l0 and the resilient discs 20. As noted above the expansion of the arresting discs serves to extrude material and more positively close the openings which the bullet makes in its travel through the resilient discs 22. The closed resilient discs 22 serve to prevent the escape of particles to the rear. Thus fragments 30 from the bullet and the arresting discs are trapped within the bullet trap assembly rather than escaping to the rear where they may strike the soldier launching the grenade.

Referring now to the FIG. 4, the end of a rifle barrel 1 is provided with a grenade launcher and flash hider 40. While the bullet trap assembly could be identical to that shown in FIGS. 1 or 2, an alternative embodiment has been shown. The tubular section 6 of the rifle grenade has been terminated at the base of the bullet trap assembly 8. While this shortens the overall length of the rifle grenade and simplifies storage requirements, it is not essential and the same rifle grenade can be used for weapons with or without the grenade launcher. Alternatively, the embodiments of FIGS. 1 and 2 can be provided with a fracture inducing groove at the base of the bullet trap 8. Then the rifleman can merely snap off the rearward portion of tube 6 if the grenade is to be used with a rifle having a grenade launcher of the type shown in FIG. 4. The bullet trap has a pliable liner 10 and an initial resilient disc 22. Following the resilient disc 22 is a bullet arresting disc 16. The remainder of the bullet trap consists of alternations of arresting discs and resilient elements. The resilient elements of FIG. 4 consist of discs 22 with spacer rings 42. The spacer rings may be fabricated of light metal, plastic or other material of sufficient strength to space the arresting and resilient discs of the bullet trap. The rings 42 are smaller in diameter than the inside diameter of the pliable envelope 10.

FIG. 5 shows the bullet trap assembly of FIG. 4 after it has stopped a bullet. An opening 50 has been pierced in the pliable envelope 10. The rearmost resilient disc 20 has been pierced by the bullet but the opening 52 has been reclosed by the resilient nature of the material. The first arresting disc 16 has been pierced by the bullet and the opening 54 remains. The expansion of the disc 16 caused by the passage of bullet has extruded some of the envelope both forwardly and rearwardly. This extruded material helps to close more positively the opening 52 in disc 22 and any additional expansion volume needed is provided by the clearance between disc 42 and the lining 10. As the bullet passes through successive arresting discs, their expansion serves to more positively seal the adjoining resilient discs. The bullet 3 finally comes to rest in the forward portion of the bullet trap, having imparted its forward momentum to the rifle grenade.

Since the expansion of the arresting discs has been taken up by deformation and compression of the casing 10, the tubular section 6 of the rifle grenade is not bulged or deformed. Therefore the rifle grenade is free to slide out of the grenade launcher 40 and is not impeded by the guiding rings of the grenade launcher. If the tubular section 6 had been bulged or deformed the grenade could either fall short of its desired trajectory, with a possibility of casualties among the firers associates, or, if the deformation was severe, become locked to the grenade launching assembly. In that case the rifle is temporarily rendered inoperative.

As in the case of the prior embodiments the closure of the openings through the resilient discs prevents the rearward escape of particles 30 consisting of fragments from the bullet 3 and the discs it has penetrated. This retention of the particles prevents injury which otherwise might occur to the individual firing the rifle grenade.

An alternative ring and disc embodiment suitable for use in the bullet trap of FIGS. 4 and 5 is shown in FIG. 6. In this case a resilient disc and ring are provided by a unitary assembly 60. This assembly has a flat disc section 62 with a spacing ring section 64. The provision of both the resilient disc and the spacing ring in a single unitary assembly simplifies the fabrication of bullet traps of the type shown in FIGS, 4 and 5.

The choice between an assembly such as that shown in FIG. 4 and that shown in FIG. 2 will depend in part upon the resilient materials used. If a material which is both resilient and quite compressible, as for example a porous or foamed plastic, is used, then the embodiment of FIG. 2 is quite effective in performance and simple to assemble. For materials which are less compressible, for example, solid plastic elements, the embodiment of FIG. 4 and the assembly of FIG. 6, provide ample space for the yieldable plastic material to flow into without bulging or deforming the tail section of the rifle grenade.

While soft metal such as lead or annealed aluminum may be used instead of plastic for the yieldable, deformable material, plastic materials provide adequate performance and will normally be cheaper and easier to fabricate. Similarly the en velope section 10 can be provided by an annealed portion forming the inside of tubular section 6 of the rifle grenade. However, this construction requires careful metallurgical control and will normally be more expensive than, for example, a plastic liner or envelope l0.

The cross sectional view of FIG. 7 illustrates a bullet trap utilizing an annealed portion to provide the function of envelope section 10. The bullet arresting portion is identical to the embodiment of FIG. 2, except for the fact that the function of the envelope 10 of FIG. 2 is performed by the annealed portion of the tube 6 of FIG. 7. As indicated by the additional cross hatching lines in the region 70, the interior portion of the tube 6 is annealed to provide a soft deformable region. The remainder of the tube 6' is not annealed so that it provides the structural strength necessary for the structural support and proper functioning of the grenade assembly.

When a bullet is arrested by the bullet trap of FIG. 7, the resilient disc 22 and bullet resistant disc 16 function in a manner identical to that described above in connection with FIGS. 2 and 3. The material and action of the resilient section 22 corresponds with that of section 22 of FIGS. 2 and 3 and the material and action of bullet resistant disc 16' corresponds with that of the disc 16 of FIGS. 2 and 3. The annealed portion 70 of tube 6' deforms in a manner corresponding to that of the deformable liner 10 of FIGS. 2 and 3. Thus the discs 16 are permitted to expand upon the passage of a bullet and the displaced annealed portion 70 is accommodated by compression of resilient disc 22.

While the above description has set forth certain preferred embodiments of my bullet trap, those skilled in the military arts will recognize that various modifications may be made without departing from the scope of the present invention.

Having thus described my invention, I claim:

1. A bullet decelerator comprising:

a housing,

a lining of pliable material within said housing,

a plurality of bullet resisting elements within said lining,

resilient elements within said lining, whereby said bullet resisting elements decelerate a bullet entering said housing, and

said resilient elements retain fragments produced by the passage of said bullet through said resisting elements and serve to protect said housing from distortion.

2. A bullet decelerator according to claim 1 wherein said resilient elements are arranged so that a resilient element is penetrated by the bullet before a resistant element and said resilient elements are alternated with said resisting elements.

3. A bullet decelerator according to claim 2 wherein the resilient elements are spaced from adjacent resisting elements by ring washers.

4. A bullet decelerator according to claim 2 wherein said resilient elements are provided with an integral spacing ring.

5. A bullet decelerator according to claim 3 wherein the centers of the spacing ring washers are filled with resilient material.

6. A bullet decelerator according to claim 2 wherein said housing has an interior portion,

said interior portion being more deformable than the remainder of said housing,

said interior portion serving as the lining of pliable material.

7. A bullet decelerator according to claim 9 wherein said deformable interior portion is provided by selective annealing of the interior of said housing.

8. A bullet decelerator for use in propelling a projectile comprising,

a housing,

a plurality of bullet resistant elements within said housing,

spacing means to separate said resistant means,

the over-all size of said resistant means being smaller than the adjoining inside dimensions of said housing,

said housing being provided with a lining of pliable material,

completely whereby said resistant means may expand under impact of the bullet without producing deformation of the housing. 9. A bullet decelerator according to claim 8 wherein resilient elements are disposed within said housing,

said resilient elements retaining fragments produced by the 5 passage of a bullet through said resistant means 

1. A bullet decelerator comprising: a housing, a lining of pliable material within said housing, a plurality of bullet resisting elements within said lining, resilient elements within said lining, whereby said bullet resisting elements completely decelerate a bullet entering said housing, and said resilient elements retain fragments produced by the passage of said bullet through said resisting elements and serve to protect said housing from distortion.
 2. A bullet decelerator according to claim 1 wherein said resilient elements are arranged so that a resilient element is penetrated by the bullet before a resistant element and said resilient elements are alternated with said resisting elements.
 3. A bullet decelerator according to claim 2 wherein the resilient elements are spaced from adjacent resisting elements by ring washers.
 4. A bullet decelerator according to claim 2 wherein said resilient elements are provided with an integral spacing ring.
 5. A bullet decelerator according to claim 3 wherein the centers of the spacing ring washers are filled with resilient material.
 6. A bullet decelerator according to claim 2 wherein said housing has an interior portion, said interior portion being more deformable than the remainder of said housing, said interior portion serving as the lining of pliable material.
 7. A bullet decelerator according to claim 9 wherein said deformable interior portion is provided by selective annealing of the interior of said housing.
 8. A bullet decelerator for use in propelling a projectile comprising, a housing, a plurality of bullet resistant elements within said housing, spacing means to separate said resistant means, the over-all size of said resistant means being smaller than the adjoining inside dimensions of said housing, said housing being provided with a lining of pliable material, whereby said resistant means may expand under impact of the bullet without producing deformation of the housing.
 9. A bullet decelerator according to claim 8 wherein resilient elements are disposed within said housing, said resilient elements retaining fragments produced by the passage of a bullet through said resistant means. 